Development of low-dislocation-density semi-insulating long 2-inch InP single crystals by the VCZ method

Abstract

Two-inch diameter 220 mm-long the semi-insulating InP single crystals with low dislocation density have been successfully developed by the VCZ (vapor pressure controlled Czochralski) method. The length of the crystals is twice as long as conventional VCZ single crystals. These crystals have been grown by combining two key technologies. One is the VCZ method, which can reduce dislocation density by suppressing the phosphorus dissociation from the crystal surface caused by a low temperature gradient. The other is a multi-zone heater method, which can achieve the temperature profile suitable for the growth of long crystals. The etch pit density across the ingot was less than 4 /spl times/ 10/sup 3/ cm/sup 2/, one order of magnitude less than that of conventional liquid encapsulated Czochralski (LEC) crystals. The dispersion of resistivity of long VCZ crystals was better than that of conventional LEC crystals. The dispersion of resistivity of long VCZ crystals was better than that of conventional LEC crystals. The residual strain of long VCZ crystals was much lower than that of conventional LEC crystals. The residual strain of long VCZ crystals was much lower than that of conventional LEC crystals. The density of hillock on the epitaxial layer could be reduced by using this long VCZ crystal as the substrate. >